State of the art microprocessors are typically equipped with on-die temperature sensors that allow a monitoring and control the die temperature during operation. Such control may in some instances take place via the use of a passive heat sink coupled with a system cooling fan, or including an active heat sink or fan sink. Other arrangements for controlling the die temperature during operation are also well known. Control of the die temperature may be triggered, for example, when the die temperature sensed by the temperature sensor reaches a threshold or activation temperature value, at which point a signal is sent to the heat management arrangement to effect temperature control.
On-die temperature sensors sometimes include thermal diodes located on the edge or corner of the die in order not to interfere with the die's circuitry. Circuitry for the diodes is typically formed along with other circuitry on the die. As a result, disadvantageously, the performance of such thermal diodes may be impacted by the die fabrication process variations, which would then negatively affect the thermal management of the die during operation. In particular, the ideality factor of the thermal diode may vary between different die production lots because of fabrication process variations between those die lots. Such fabrication process variations would typically introduce fabrication process variations as between the diodes on each different unit, which would mean varying performances as between those diodes. As die measurements shrink with advancements in microelectronic fabrication, fabrication process changes as between different die lots are apt to introduce larger and larger temperature measurement errors by the currently used on-die thermal diodes.
In addition, an ideality factor of the same thermal diode on the same die may vary as the temperature of the die changes. For the same diode on a given die, a temperature change of about 75 degrees Celsius can result in a change in the ideality factor of about 0.1, which can negatively impact a performance of the thermal sensor.
A variability of ideality factors can result in appreciable die temperature measurement errors ranging from about 39 to about 85 degrees Celsius when using analog devices to measure the thermal diode temperature. Such errors can negatively impact a control of a heat management arrangement, which control relies on accurate die temperature measurements by the thermal diode. For example, a control of the speed and acoustic noise of a cooling fan may be negatively affected by errors resulting from variations of a thermal diode's ideality factor. A unit by unit calibration of the diodes would clearly be costly and cumbersome, and not suited for high volume manufacturing.
The prior art fails to provide a reliable microelectronic package structure and method to monitor and control a temperature of a die during its operation.
For simplicity and clarity of illustration, elements in the drawings have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Where considered appropriate, reference numerals have been repeated among the drawings to indicate corresponding or analogous elements.